moby/pkg/progress/progress.go
Tibor Vass 7dac70324d pkg/progress: work around closing closed channel panic
I could not reproduce the panic in #37735, so here's a bandaid.

Signed-off-by: Tibor Vass <tibor@docker.com>
2018-09-06 20:20:12 +00:00

93 lines
2.4 KiB
Go

package progress // import "github.com/docker/docker/pkg/progress"
import (
"fmt"
)
// Progress represents the progress of a transfer.
type Progress struct {
ID string
// Progress contains a Message or...
Message string
// ...progress of an action
Action string
Current int64
Total int64
// If true, don't show xB/yB
HideCounts bool
// If not empty, use units instead of bytes for counts
Units string
// Aux contains extra information not presented to the user, such as
// digests for push signing.
Aux interface{}
LastUpdate bool
}
// Output is an interface for writing progress information. It's
// like a writer for progress, but we don't call it Writer because
// that would be confusing next to ProgressReader (also, because it
// doesn't implement the io.Writer interface).
type Output interface {
WriteProgress(Progress) error
}
type chanOutput chan<- Progress
func (out chanOutput) WriteProgress(p Progress) error {
// FIXME: workaround for panic in #37735
defer func() {
recover()
}()
out <- p
return nil
}
// ChanOutput returns an Output that writes progress updates to the
// supplied channel.
func ChanOutput(progressChan chan<- Progress) Output {
return chanOutput(progressChan)
}
type discardOutput struct{}
func (discardOutput) WriteProgress(Progress) error {
return nil
}
// DiscardOutput returns an Output that discards progress
func DiscardOutput() Output {
return discardOutput{}
}
// Update is a convenience function to write a progress update to the channel.
func Update(out Output, id, action string) {
out.WriteProgress(Progress{ID: id, Action: action})
}
// Updatef is a convenience function to write a printf-formatted progress update
// to the channel.
func Updatef(out Output, id, format string, a ...interface{}) {
Update(out, id, fmt.Sprintf(format, a...))
}
// Message is a convenience function to write a progress message to the channel.
func Message(out Output, id, message string) {
out.WriteProgress(Progress{ID: id, Message: message})
}
// Messagef is a convenience function to write a printf-formatted progress
// message to the channel.
func Messagef(out Output, id, format string, a ...interface{}) {
Message(out, id, fmt.Sprintf(format, a...))
}
// Aux sends auxiliary information over a progress interface, which will not be
// formatted for the UI. This is used for things such as push signing.
func Aux(out Output, a interface{}) {
out.WriteProgress(Progress{Aux: a})
}